1. Field of the Invention.
The present invention relates to a viscosity measurement apparatus to measure the viscosity of fluid under pressure in a fluid system. In particular, the present invention relates to a viscosity measurement apparatus that may be utilized on-line in a fluid system and may thereafter be reset to initiate a further measurement.
2. Prior Art.
Viscosity, the resistance a fluid presents to flow, is often an important measurement. Viscosity is measured by observing the time required for a certain volume of the liquid to flow through a short tube of small bore. While it is often determined for scientific or technical purposes, the viscosity is important in industrial applications. As hydraulic fluid ages, viscosity increases slowly. These increases in viscosity are caused by fluid base and additive oxidation. Unusually high operating temperatures accelerate the process. Therefore, rapid swings in fluid viscosity may signal the presence of system hot spots. Generally, any swing in viscosity of 10% or more is an indication that the fluid is nearing the end of its useful life. If the viscosity of a fluid varies, it may indicate a problem with the fluid system. Accordingly, it is important to monitor the viscosity in a fluid system.
While it is well known to periodically draw a sample from the fluid system and subject it to testing, it is desirable to be able to determine the viscosity of the fluid on-line.
It is also desirable to be able to reset the measurement apparatus to take additional, periodic tests of the viscosity as desired.
It is also desirable to rapidly calculate the viscosity and be able to transfer or deliver this information for analysis.
It is also desirable to provide a lightweight and portable viscosity measurement apparatus.